1. Field of the Invention
This invention is directed to a hydrogen bronze catalyst and a process for using it in hydrotreating various petroleum resids.
2. Discussion of the Prior Art
It is well known that many if not most petroleum base stocks contain contaminants, as for example, sulfur, nitrogen and metals. It is desirable particularly if these feedstocks are to be further processed that the contaminants be removed. This is an operation usually requiring use of a catalyst.
It has been conventional in the art to effect sulfur removal from hydrocarbon stocks by subjecting them to treatment with hydrogen at elevated temperature and pressure while in contact with a catalyst containing hydrogenating components. Typically the hydrogenating components of such prior art catalysts are Group VIB or Group VIII metals, or other oxides or sulfides. These hydrogenating components may be supported on a variety of well known carriers, for example, alumina, kieselguhr, zeolitic molecular sieves and other materials having high surface areas: U.S. Pat. No. 4,080,296. U.S. Pat. No. 3,546,103 teaches hydrodesulfurization with a catalyst of cobalt and molybdenum on an alumina base. U.S. Pat. No. 3,755,146 describes a process for preparing lube oils characterized by low pour points which utilizes a catalyst mixture comprising hydrogenation components, a conventional cracking catalyst which can be either crystalline or amorphous and a crystalline aluminosilicate of the ZSM-5 type.
Hydrotreating of distillates may be defined simply as the removal of sulfur, nitrogen and metal compounds by selective hydrogenation. The hydrotreating catalysts used commercially are cobalt plus molybdenum or nickel plus molybdenum used in the sulfided forms and impregnated on an alumina base. The hydrotreating operating conditions are such that appreciable hydrogenation of aromatics does not occur; these are about 1,000 to 2,000 psi hydrogen and about 700.degree. F. The theoretical hydrogen consumption should be that required to hydrogenate the sulfur, nitrogen and metal containing molecules and produce hydrogen sulfide and ammonia. However, the desulfurization reactions are invariably accompanied by small amounts of hydrogenation and hydrocracking, the extent of which depends on the nature of the feedstock and the severity of desulfurization.
However, neither the prior art mentioned above nor any art known to applicants have combined in a single stage operation the hydrotreating of petroleum resids with a thermally stable catalytic support material containing at least about 10 wt % layered metal oxide hydrogen bronze. This hydrotreatment of petroleum resid results in an improved demetallized product compared to that obtained with CoMo/Al.sub.2 O.sub.3 catalyst.
Because of the high pressures required for the hydroprocessing of resids, it is extremely desirable from an economic standpoint to minimize reactor volume. Use of these layered metal oxide bronze materials with a suitable support for upgrading of resids will allow the refiner to attain the required degree of metals removal with less catalyst and therefore in a smaller reactor. Alternatively, using the hydrogen bronze based catalyst in existing reactors will allow refiners to run at lower reaction severities or to attain process resid with improved quality. The process of the present invention would apply to, for example, FCC feed pretreatment. With this in mind, applicants will proceed with a summary of the novel features of the present invention.